The following abbreviations are herewith defined, at least some of which are referred to within the following description.
3GPP Third Generation Partnership Project
ACK Positive-Acknowledgment
ANDSF Access Network Discovery and Selection Function
AP Access Point
APN Access Point Name
AS Access Stratum
BLER Block Error Ratio
BPSK Binary Phase Shift Keying
CAZAC Constant Amplitude Zero Auto Correction
CCA Clear Channel Assessment
CCE Control Channel Element
CP Cyclic Prefix
CQI Channel Quality Information
CSI Channel State Information
CRS Cell-Specific Reference Signal
CSS Common Search Space
DCI Downlink Control Information
DL Downlink
EDGE Enhanced Data Rates for Global Evolution
eNB Evolved Node B
EPDCCH Enhanced Physical Downlink Control Channel
E-RAB E-UTRAN Radio Access Bearer
ETSI European Telecommunications Standards Institute
E-UTRAN Evolved Universal Terrestrial Radio Access Network
FBE Frame Based Equipment
FDD Frequency Division Duplex
FDMA Frequency Division Multiple Access
FEC Forward Error Correction
GERAN GSM/EDGE Radio Access Network
GPRS General Packet Radio Service
GSM Global System for Mobile Communication
GTP GPRS Tunneling Protocol
HARQ Hybrid Automatic Repeat Request
H-PLMN Home Public Land Mobile Network
IoT Internet-of-Things
IP Internet Protocol
ISRP Inter-System Routing Policy
LAA Licensed Assisted Access
LBE Load Based Equipment
LBT Listen-Before-Talk
LTE Long Term Evolution
MCL Minimum Coupling Loss
MCS Modulation and Coding Scheme
MME Mobility Management Entity
MU-MIMO Multi-User, Multiple-Input, Multiple-Output
NACK or NAK Negative-Acknowledgment
NAS Non-Access Stratum
NB Narrowband
NBIFOM Network-Based IP Flow Mobility
NB-IoT Narrowband IoT
NB-PBCH Narrowband PBCH
NB-PCID Narrowband PCID
NB-PDCCH Narrowband PDCCH
NB-PDSCH Narrowband PDSCH
NB-PSS Narrowband PSS
NB-SSS Narrowband SSS
OFDM Orthogonal Frequency Division Multiplexing
PCell Primary Cell
PBCH Physical Broadcast Channel
PCID Physical Cell Identification (“ID”)
PCO Protocol Configuration Options
PCRF Policy and Charging Rules Function
PDCCH Physical Downlink Control Channel
PDCP Packet Data Convergence Protocol
PDN Packet Data Network
PDSCH Physical Downlink Shared Channel
PDU Protocol Data Unit
PGW Packet Data Network Gateway
PHICH Physical Hybrid ARQ Indicator Channel
PLMN Public Land Mobile Network
PRACH Physical Random Access Channel
PRB Physical Resource Block
PSS Primary Synchronization Signal
PUCCH Physical Uplink Control Channel
PUSCH Physical Uplink Shared Channel
QoS Quality of Service
QPSK Quadrature Phase Shift Keying
RAB Radio Access Bearer
RAN Radio Access Network
RAR Random Access Response
RE Resource Element
RRC Radio Resource Control
RS Reference Signal
RX Receive
SC-FDMA Single Carrier Frequency Division Multiple Access
SCell Secondary Cell
SCH Shared Channel
SGW Serving Gateway
SIB System Information Block
SINR Signal-to-Interference-Plus-Noise Ratio
SR Scheduling Request
SSS Secondary Synchronization Signal
TAU Tracking Area Update
TBS Transport Block Size
TCP Transmission Control Protocol
TDD Time-Division Duplex
TDM Time Division Multiplex
TED Tunnel Endpoint Identification (“ID”)
TX Transmit
UCI Uplink Control Information
UE User Entity/Equipment (Mobile Terminal)
UL Uplink
UMTS Universal Mobile Telecommunications System
V-PLMN Visited Public Land Mobile Network
WiMAX Worldwide Interoperability for Microwave Access
WLAN Wireless Local Area Network
In wireless communications networks, a frame structure for LTE FDD may be used. A radio frame of 10 milliseconds (“ms”) may include 10 subframes, each of which is 1 ms. Each subframe further may include two slots, each of which is 0.5 ms. Within each slot, a number of OFDM symbols may be transmitted. The transmitted signal in each slot on an antenna port may be described by a resource grid comprising NRBDLNscRB subcarriers and NsymbDL OFDM symbols, where NRBDL is number of RBs in the DL (which is dependent on the transmission bandwidth of a cell); NscRB is the number of subcarriers in each RB; and each subcarrier occupies a certain frequency of size Δf. The values of NscRB, Δf, and NsymbDL may depend on a cyclic prefix as shown in Table 1.
TABLE 1ConfigurationNscRBNsymbDLNormal Cyclic PrefixΔf = 15 kHz127Extended Cyclic PrefixΔf = 15 kHz6Δf = 7.5 kHz243
In certain configurations, an antenna port may refer to a logical antenna port (i.e., it may not necessarily refer to a physical antenna or antenna element). Mapping between an antenna port and physical antenna element(s) may be implementation specific. In other words, different devices may have a different mapping of physical antenna element(s) to the same antenna port. A receiving device may assume that the signals transmitted on the same antenna port go through the same channel. Moreover, a receiving device cannot assume signals transmitted on different antenna ports go through the same channel.
Reference signals exist in the current LTE system. A reference signal (“RS”) may be transmitted on an antenna port, and by using the RS, the receiver may estimate the channel which the data transmitted on the antenna port also experiences. Both cell-specific and UE-specific RSs exist in the current LTE system. While a cell-specific reference signal (“CRS”) is common to all UEs in a cell, the UE specific reference signal of different UEs may be different. A UE may use the CRS for PBCH demodulation, PDCCH demodulation, PDSCH demodulation, and channel state information (“CSI”) measurement.
In LTE, the DL CRS sequence and REs that are used to carry the CRS may be dependent on the cell's PCID. Before a UE is connected to a serving cell, the UE may perform a cell search procedure. Each cell may transmit a primary synchronization signal (“PSS”) and a secondary synchronization signal (“SSS”), which collectively define the PCID of the cell. The UE may search for the PSS/SSS on a frequency raster of every 100 kilohertz (“kHz”). Once the UE detects the PSS/SSS, the UE then may know the PCID of the cell. Consequently, the UE may derive the CRS sequence and the time-frequency resources carrying each of the CRS sequence. Moreover, by detecting the PSS/SSS, the UE may further obtain the subframe synchronization (e.g., the subframe and slot timing) and CP type (e.g., either normal CP or extended CP) of the cell. After the UE obtains the PSS/SSS, the UE may demodulate the PBCH. In certain configurations, the CRS sequence may be used to demodulate the PBCH. In various configurations, the PBCH is transmitted in the center 6 PRBs of an LTE system bandwidth. Moreover, the UE may derive the CRS for PBCH demodulation irrespective of the system bandwidth.
NarrowBand IoT (“NB-IoT”) specifies a radio access technology for cellular internet of things that addresses improved indoor coverage, support for massive number of low throughput devices, low delay sensitivity, ultra-low device cost, low device power consumption, and (optimized) network architecture.
NB-IoT may support the following different modes of operation: “Stand-alone operation” utilizing, for example, the spectrum currently being used by GERAN systems as a replacement of one or more GSM carriers; “Guard band operation” utilizing the unused resource blocks within an LTE carrier's guard-band; and “In-band operation” utilizing resource blocks within a normal LTE carrier.
An NB-IoT may support an RF and baseband bandwidth of 180 kHz, which is equivalent to one LTE Physical Resource Block (“PRB”). NB-IoT downlink may be based on orthogonal frequency division multiple access (“OFDMA”), with 15 kHz subcarrier spacing. Thus, for guard-band and in-band operations, NB-IoT may maintain orthogonality with adjacent LTE PRBs.
A cell supporting NB-IoT may transmit a NB-IoT synchronization signal, comprising a NB-IoT primary synchronization signal (“NB-PSS”) and a NB-IoT secondary synchronization signal (“NB-SSS”). By detecting the NB-PSS/NB-SSS, a NB-IoT UE may derive the PCID of the NB-IoT cell (“NB-PCID”). For in-band NB-IoT operation, the NB-PCID may or may not be the same as the PCID of the LTE carrier. By detecting the NB-PSS/NB-SSS, the NB-IoT UE may also derive the subframe synchronization (e.g., the subframe and slot timing). By detecting the NB-PSS/NB-SSS, the NB-IoT UE may also derive one or more the following information: the CP type of the NB-IoT cell; and the operation mode of the NB-IoT cell.
After the NB-IoT UE detects the NB-PSS/NB-SSS and retrieves the necessary information (e.g. NB-PCID, subframe synchronization), the NB-IoT UE may obtain the PBCH of the NB-IoT cell (“NB-PBCH”). In order to obtain the NB-PBCH, the NB-IoT UE needs to know the RS (including the RS sequence and the time-frequency resources used to transmit the RS sequence) that can be used to demodulate the NB-PBCH, and the frequency location of the NB-PBCH.